Quran 18:104 — The Cave (Al-Kahf)

"They are the ones whose works in this life are totally astray, but they think that they are doing good."

[18:103] Say, "Shall I tell you who the worst losers are?

[18:105] Such are the ones who disbelieved in the revelations of their Lord and in meeting Him. Therefore, their works are in vain; on the Day of Resurrection, they have no weight.